PS6-28. Effects of Algal Docosahexaenoic Acid in Dog Diets on Fecal Characteristics, Apparent Total Tract Digestibility of Macronutrients.

Abstract Algal meal is an emerging sustainable ingredient in animal nutrition, particularly valued for its high content of docosahexaenoic acid (DHA), an essential omega-3 fatty acid. It offers a renewable alternative to fish oil, helping address concerns related to environmental impact, supply variability, and oxidative stability. DHA plays important roles in neural function, immune response, and overall health in companion animals. However, there is limited information in the literature on the effects of supplementing algal DHA meal in extruded diets for adult dogs. This study aimed to evaluate the effects of dietary supplementation of algal DHA meal on fecal characteristics, apparent total tract digestibility of macronutrients. We hypothesized that dietary supplementation with algal DHA meal would have no negative effects on food intake, fecal characteristics, apparent total tract digestibility (ATTD) of macronutrients compared extruded diets containing fish oil or chicken fat. Thirty-two healthy adult beagles (20 females, 12 males; avg. age = 5.1±1.6 years; avg. body weight = 11.0±2.3 kg) were fed one of 4 diets: a Control diet with 10% chicken fat, or a diet with 2% fish oil, 2% algal meal, and 4% algal meal, as partial replacement of chicken fat in this completely randomized design study. One dog was excluded due to health issues unrelated to this study. Following a 15-day adaptation period where dogs were fed the Control diet, dogs were randomly assigned to one of the 4 dietary treatments for 90 days. Fresh fecal samples were collected on days 0, 30, 60, and 90. Total feces were collected for 5-days; days 85-90 of experimental period. There was no significant difference (P > 0.05) in food intake, fecal output, and fecal scores across dietary treatments. Apparent total tract digestibility of macronutrients did not differ significantly (P > 0.05) among treatment groups for dry matter, organic matter, crude protein, and acid-hydrolyzed fat. However, dogs fed 4% algal meal had higher (P < 0.0001) digestible energy compared with dogs fed Control diet. Conclusively, this study shows that utilizing up to 4% of algal meal in extruded diets for adult dogs improved energy digestion and maintained fecal quality.